Studies Of Modified Lignosulfonates And Their Capabilities

It is nearly twelfth century ago, a famous philosopher, in China, named Zhu Xi once pointed out that it is no trash in the world. Now people pay more attention to the regenerated resource than ever before. At the same time, with the development of "green concrete", superplasticizers become more and more important. But common lignosulfonate, as a kind of water reducer, has a lot of disadvantages, such as postponing the concreting hours and reducing the strength of concrete. To reduce the waste of resource, lignosulfonate should be modified to meet the demand of superplasticezer.This paper is concerned with chemic modification, multiplex modification and biodegraded modification. After each modification, modified product is tested with cement and concrete. At last, the mechanism of lignosulfonates, as water reducers, is discussed. In chemic modification, both two functional groups, -COOH and -SO3H, are considered, which differs from what people did before, and the performance of this product improved so much. When it is put with the dosage of 0.5%, the ratio of reduced water to concrete is 21.2%, and the compression strength ratio of concrete hardened for 7d and 28d, is 119 and 116, which approach to the level of NF. In multiplex modification, lignosulfonate before modification is mixed with NF and PC respectively, and so does the product after modification. When OGS/NF=0.2%/0.2% and OGS/PC=0.2%/0.06%, the ratio of reduced water to concrete is 23.0% and 20.0%, and the compression strength ratio of concrete hardened for 7days and 28days, is 115 and 103 for the former and 111 and 102 for the later. These years, the study of biodegraded lignosulfonate is become more and more important, but biodegraded product is never used as water reducers. On the conditions of detailed study of the mechanism of biodegradation, together with the character of lignosulfonate, the possibility of biodegraded product used as water reducers is put forward, and is certified with experiments. When it is put with the dosage of 0.5%, the flowability of cement is to 180mm, and 52mm higher than that of unmodified lignosulfonate.It is much effective for the study of lignosulfonate modifications, and the fruits can be the foundition for the further study, especially for the water reducer of biodegraded lignosulfonate.